1. Field of the Invention
This invention relates to the field of power supplies, and particularly to reducing the idle power consumption in power supplies for adapters and mobile products.
2. Description of the Related Art
Individuals and corporations are becoming increasingly aware of their energy consumption and are actively seeking to reduce it. Whether the primary motivation is to reduce the size of a carbon footprint or save on energy costs, consumers are demanding more energy efficient and eco-friendly products from manufacturers.
In our age of ubiquitous electronic devices, consumers and regulators are becoming increasingly aware of the energy costs of electronics. A common culprit of energy inefficiency is the so-called energy vampire. Common electrical devices, such as computers, televisions, and appliances require standby power and consume electricity even when the device is off. Standby power accounts for the power necessary to allow the device to maintain information even when it is off, respond to remote controls, or provide other functions. It also accounts for parasitic losses in the device. The power consumed in standby mode is comparable to the power consumed in active mode for many devices.
Many devices, such as the laptop computer 110, personal data assistant (“PDA”) 112, and cellular phone 114 shown in FIG. 1, plug into a charger such as the charger 100. Many consumers leave the chargers 100 plugged in after they disconnect the device that they were charging. These disconnected chargers 100 continue to consume energy even when they are no longer providing any valuable function. Arguably, these losses in adapters are even worse than those due to standby power consumption since the power is entirely wasted and provides no functional value to the owner.
The EPA estimates that the power consumed by devices that are off or by chargers 100 left plugged in amounts to approximately 45 billion kilowatt-hours of electricity per year and costs upwards of 3.5 billion dollars annually. Given these significant costs, industry is focusing on ways to reduce the power consumed by the electronic devices they manufacture. What is needed is a process, apparatus, and system for reducing the amount of power consumed in a power supply when it is idle; that is, when it is not actively providing power to an electronic load.